The Internet, often called simply "the Net," is a worldwide system of computer networks. It was conceived by the Advanced Research Projects Agency (ARPA) of the U.S. government in 1969 and was called the ARPAnet. The original intent was to construct a network that would continue to function even if a large portion of it were destroyed, in the event of nuclear war, for example.

The Internet is now a public, self-sustaining facility accessible to millions of people worldwide. Physically, the Internet uses a portion of the total resources of all the currently existing public telecommunication networks. Technically, what distinguishes the Internet as a cooperative public network is its use of a set of protocols called TCP/IP (Transmission Control Protocol / Internet Protocol).

Overview of the Internet:

For many Internet users, electronic mail (e-mail) has practically replaced the Postal Service for short written transactions. Electronic mail is the most widely used application on the Net. To use e-mail, you need an Internet address. This uniquely identifies you on the Net, so you will receive all messages intended for you, and (ideally) no messages not intended for you.

It is also possible to carry on "conversations" with other computer users via the Internet. This is called IRC (Internet Relay Chat). Typing and reading messages in real time is more personal than e-mail, but it is less personal than talking on the telephone. However, Internet telephony hardware and software is available that allows real-time voice conversations on the Net. These programs work best when the Net is not being heavily used. When there are many people using the Net, Internet telephony becomes somewhat less reliable and the audio quality is compromised.

One of the most important features of Internet is the fact that it can get you in touch with myriad sources of information. You can do library research without having to commute or travel. You can get data from corporations, educational institutions, and government agencies without having to order it via mail or telephone.

The most widely used part of the Internet is the World Wide Web (often abbreviated "WWW" or called "the Web"). Its outstanding feature is hypertext, a method of instant cross-referencing. In most Web sites, certain words or phrases appear in text of a different color than the rest; often this text is also underlined. When you select one of these words or phrases, you will be transferred to a site relevant to the word or phrase. Sometimes there are buttons, images, or portions of images that are "clickable." If you move the pointer over a spot on a Web site and the pointer changes into a hand, this indicates that you can click and be transferred to another site.

There are various programs available for "Web surfing." These programs are called browsers. The most popular browsers are Microsoft Internet Explorer and Netscape Navigator. The appearance of a particular Web site may vary slightly depending on the browser you use. Also, later versions of a particular browser are able to render more "bells and whistles" such as animation, virtual reality, sound, and music files, than earlier versions.